1. Field of the Invention
The present invention relates to a process cartridge and an image forming apparatus on which said process cartridge can be mounted. Herein, the image forming apparatus may be, for example, an electrophotographic copying machine, a word processor, a facsimile apparatus, a laser beam printer or an LED printer.
2. Related Background Art
The image forming apparatuses, such as a printer, perform the recording of an image in such a manner as to form a latent image on an image bearing member uniformly charged by selective exposure, develop this latent image with toner, and transfer the toner image onto the recording medium. With such apparatuses, the maintenance of units is not permitted except by the expert serviceman, causing an inconvenience for the user. Thus, an image forming apparatus has been put to practical use in which the image bearing member, electrifier, developing unit, and cleaning unit are integrated into a unit structure as a cartridge, so that the refilling of toner or the replacement of image bearing member components reaching the end of their life is enabled by the user mounting the cartridge on the apparatus itself to facilitate the maintenance.
Such process cartridge has a main component imprinted or marked by permanent ink with a lot number. Also, when the permanent ink is used, it is marked on the sheet metal portion, such as a cleaning blade. This imprinting or permanent ink is provided to reveal the manufacturing time or a manufacturer of components used in the cartridge, when such components causes a trouble.
However, the process cartridge with the above constitution had the following problems. The imprinting of components used in the process cartridge may be difficult, although it can be made, if the outer package is made of thermoplastic. Also, with the imprinting method, only a small amount of information can be written. On the other hand, when permanent ink is used to write information, there is a wide scope of selection for recording materials, but the information often disappears due to friction with any other objects.
Also, with the process cartridge mentioned above, the components are increasingly subjected to reuse or recycling for the purposes of resource saving, energy saving and reduction of contaminants, owing to the recent increased concern for environmental protection. For example, in the process cartridge, the components for rollers such as a charging roller, a developing sleeve, a transfer roller, a fixing roller, a cleaning roller, or a conveying roller, have a longer life span, and are usable even after the use of toner within the cartridge. Therefore, in recent years, cartridges remaining after the depletion of toner tend to be reused or recycled as components for the rollers mentioned above.
Thus, in recycling it is preferable to assess the extend to which the the component has been used, that is, to what extent the component has deteriorated, including the influence of its service environment, and to determine whether the component is reusable, or should be destroyed or otherwise reused in any other form (e.g., a resin component made of pellets, and mixed into virgin material to provide moldings).
Herein, it is typical to indicate a lot number in the main components of the process cartridge, which reveals the production time of cartridge. However, because the life of cartridge components is affected by the service environment, the production time and component life are not necessarily consistent. Accordingly, in recycling the process cartridge, it is necessary to examine precisely whether individual components are reusable or not after decomposition and cleaning, which often took a large amount of time and money.